Q22 of 203 Page 172

How many atoms are there in 0.25 mole of hydrogen?

1 mole of hydrogen contains = 6.022 × 10²³ atoms of hydrogen

So, 0.25 moles of hydrogen will have = 6.022 × 10²³ × 0.25 = 1.50 × 10²³ atoms of hydrogen.

Calculate the mass of 3.011 × 10²⁴ atoms of carbon.

If 6 g of oxygen contains 1 mole of oxygen atoms, calculate the mass of one atom of oxygen.

Calculate the number of moles in 12.044 × 1025 atoms of phosphorus.

Calculate the number of moles present in a drop of chloroform (CHCl₃) weighing 0.0239 g. (Atomic masses: C = 12 u; H = 1 u; Cl = 35.5 u)